fix(words): untrack the langs-registration $effect (no reactive loop)

Regression from the onMount→$effect conversion (increment 3): eidos.langs.extend
both reads AND mutates the reactive langs schema, so the $effect tracked that
read, the mutation retriggered it, and it looped — re-extending the bundles
thousands of times, each logging a DEV leaf-overwrite warning (~90k warnings,
hung the editor page). Wrapped the body in untrack ⇒ the effect has no deps ⇒
runs exactly once on mount, like the old onMount. Verified: words page loads
fast, zero console warnings, editor + inspector render. api-contract test still
green (untrack is not flagged).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/uix/eidos/components/words/words.svelte

@@ -13,6 +13,7 @@
 	 * (builder-style, always visible), a slide-in drawer, a popover, or
 	 * none. The same `<WordsInspector>` body is reused across all of them.
 	 */
+	import { untrack } from 'svelte';
 	import { ActiveEidos } from '$uix/eidos';
 	import * as Words from '$soma/components/words';
 	import { Button } from '$uix/eidos/components/button';
@@ -47,16 +48,19 @@
 	// client pass emit different markup and hydration bails. Defer the
 	// editor to the client; SSR + first paint render the empty frame.
 	let mounted = $state(false);
-	// Client-only activation + one-time langs registration. Reads nothing
-	// reactive, so this $effect runs exactly once on mount (the Svelte 5 way,
-	// no lifecycle import). Register the inspector's localized strings into the
-	// active langs schema — without this every label resolves to the inline
-	// English fallback regardless of locale. `extend` deep-merges so app-level
-	// overrides at the same path applied AFTER mount still win.
+	// Client-only activation + one-time langs registration. `langs.extend` BOTH
+	// reads and mutates the reactive langs schema, so it MUST run untracked —
+	// otherwise this $effect tracks that read, the mutation retriggers it, and it
+	// loops, re-extending the bundle thousands of times (each logging a DEV
+	// leaf-overwrite warning). untrack ⇒ the effect has no deps ⇒ runs once on
+	// mount. Registers the inspector's localized strings so labels localize
+	// instead of falling back to the inline English.
 	$effect(() => {
-		mounted = true;
-		eidos.langs.extend('components.words.inspector', WORDS_INSPECTOR_BUNDLE);
-		eidos.langs.extend('components.words.menu', WORDS_MENU_BUNDLE);
+		untrack(() => {
+			mounted = true;
+			eidos.langs.extend('components.words.inspector', WORDS_INSPECTOR_BUNDLE);
+			eidos.langs.extend('components.words.menu', WORDS_MENU_BUNDLE);
+		});
 	});
 
 	let contentEl = $state<HTMLDivElement | null>(null);